sol-6 is terra-6. They figure that no one was using terra and they could bring the speed and cost saving of terra distilled on astra, but rebranded as the more popular sol.
Back fired because of opus 5.5.
So now we get the real sol-6 as sol-6.1, and OpenAI will eat the cost to stay competitive.
This could be invalidated if sol-6.1 is the same speed as sol-6.